In recent years, a variety of photoelectric elements are being used, including photoelectrochemical elements such as photoelectric conversion-based electricity-generating elements including photovoltaic batteries and solar batteries, light-emitting elements, electrochromic display elements, optical display elements such as electron papers, electrochemical elements such as batteries and electrostatic capacitors, non-volatile memories and arithmetic elements, electric elements such as transistors, sensor elements for detecting the temperature/humidity/amount of light/amount of heat/pressure/magnetic force or the like.
Required of an electron transport layer provided in these photoelectric elements is the property of high electron transport; in addition, the size of the surface area of the reaction interface is important, which is where electrons are generated by energies from outside and where electrons injected from outside act as well. In prior art, such electron transport layer is formed from metal, organic semiconductor, inorganic semiconductor, electro-conductive polymer, electro-conductive carbon or the like.
For instance, in a photoelectric conversion element, a electron transport layer for transporting electrons is made from an organic compound having electron as carriers, such as, fullerene, peryrene derivatives, polyphenylenevinylene derivatives and pentacene, the electron transport capabilities of these substances are improving the conversion efficiency (refer to Non-Patent Reference 1 regarding fullerene, refer to Non-Patent Reference 2 regarding peryrene derivatives, and refer to Non-Patent Reference 3 regarding polyphenylenevinylene derivatives).
In addition, in regard to molecular element-type solar batteries, forming a structure comprising chemically bonded electron-donating molecule (donor) and electron-accepting molecule (acceptor) into a thin film over a substrate has also been reported (refer to Non-Patent Reference 4).
Non-Patent Reference 1: P. Peumans, Appl. Phys. Lett., No. 79, 2001, p. 126
Non-Patent Reference 2: C. W. Tang, Appl. Phys. Lett., No. 48, 1986, p. 183
Non-Patent Reference 3: S. E. Shaheen, Appl. Phys. Lett., No. 78, 2001, p. 841
Non-Patent Reference 4: “Bunshi Taiyo Denchi no Tenbo (Development of molecular-based solar cells)” by Hiroshi Imahori, Shunichi Fukuzumi, July 2001 p. 41 (Japan Chemical Industry Association)